The present invention relates to a disc drive apparatus for driving various discs such as a magnetic disc, a video disc, and an original disc for the video disc, using a turntable.
A conventional disc drive apparatus may be used in an inspection unit for inspecting surface defects such as scratches, flaws and cracks in the original disc of an optical video system. The disc drive apparatus of this type has a turntable, a turntable support for rotatably supporting the turntable, and driving means such as a motor for driving the turntable.
A shaft which is fitted in a central hole of a disc extends at the rotational center of the turntable. Female threads are formed on the rotational center of the shaft. A pressing member has male threads and a pressing pad on the lower surface thereof. These male threads engage with the female threads.
The disc with a central hole is coaxial with the turntable since the shaft on the turntable is fitted into the hole. Further, the female threads of the shaft of the turntable engage with the male threads of the pressing member. Therefore, the disc with a central hole is clamped between the pressing pad of the pressing member and the upper surface of the turntable.
In the conventional disc drive apparatus of this type, discs with different sized central holes and a disc without a central hole cannot be used. Since the disc is firmly clamped between the pressing pad of the pressing member and the upper surface of the turntable, scratches tend to be formed on the surface of the disc.